Furnace-regulator system



v 1,506,758 (5. M. LITTLE FURNACE REGULATOR SYSTEM Filed Oct. 29. 1920Sept. 2 1924B \NVENTOR f/fl/MZZZV/f AII'TORNEY WITNESSES:

Patented Sept. 2, 1924,

UNITED STATES PATENT orrics.

GEORGE M. LITTLE, 01f PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSEELECTRIC 8:; MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

FURNACE-REGULATOR SYS'IEK.

Application filed ctober29, 1920. Serial No. 420,496.

To all whom it may concern:

Be it known that I, Gnonon M. LITTLE, a citizen of the United States,and a resident of Pittsburgh, in the county of Allegheny and State of.Pennsylvania, have invented anew and useful Improvement in Furnace-Regulator Systems, of which the following is a specification.

My invention relates to regulator systems and, particularly, toregulator systems for governing the operation of electric furnaces.

One object of my invention is to provide a furnace-regulator system thatshall em body two members having relative elonga tion in accordance withvariations in furnace temperature, and that shall utilize such relativeelongation between the members for controlling the current imput to thefurnace.

In an electric furnace and, particularly,

in an electric furnace of the resistor type, trouble is oftenencountered inv so controlling the power imput as to maintain thefurnace temperature within certain predetermined limits.

In a regulator system constructed in accordance with my invention, twotubes, preferably composed of aluminum, are mounted in parallelrelation, and one of them is heated in accordance with the fur nacetemperature. A fluid system, which has a constant head and which passesthrough the furnace, is so connected to the two tubes as to effectrelative elongation between the two tubes in accordance with variationsof furnace temperature. Such relative elongation between the tubes isutilized for operating a controller to govern the current imput to thefurnace.

In the accompanying drawing,

Figure 1 is a diagrammatic view of a furnace-regulator systemconstructed in accordance with my invention;

Fig. 2 is a plan view of the two tubes and the means connected theretofor measuring the relative elongation between them;

.Fig. 3 is a diagrammatic view of the transformer connections for thefurnace; and

Fig. 4 is a diagrammatic view of a modification of the regulator systemshown in Fig. 1.

Referring to the drawing, an electric furnacc 1, of the resistor type,comprises a heating chamber 2, which is surrounded by walls 3 of anysuitable refractory and heat- Insulating material. A resistor 4, of anysuitable type, is connected to a transformer 5 and is located, in anyconvenient manner, within the chamber 2.

The transformer 5 comprises a secondary winding 6, which is directlyconnected to the resistor 4, and a primary winding 7, which is providedwith a plurality of taps 8. One terminal of the primary winding 7 isdirectly connected to one side of a supply circuit comprising conductors9 and 10. The taps 8 are adapted to be connected to the other side ofthe supply circuit through controller segments 11 and a brush member 12which passes over the segments 11. The brush member 12 and the segments11 con stitute a portion of a controller for governmg the current imputto the furnace.

The brush member 12 is preferably operated by a fluid device 13, and thelatter is controlled by a thermal device 14. The thermal device 14: comrises two tubes 15 and 16, which are prei rably composed of aluminum andare mounted within a suitable box 17. The tubes 15 are surrounded by anysuitable heat-insulating material, such as asbestos 18, and are heldtogether, near the bottom, by a clamp 19, The clamp 19 ispreferablycomposed of some heat-insulating material and not only serves to holdthe tubes 15 and 16 within the box 17 but also to prevent relativemovement between the tubes at one end thereof in order that the relativeelongation between such tubes may be readily measured. The tube 16 isconnected to any suitable source of constant fluid pressure 20, and thetube 15 is so bent as to empty into any convenient drain 21.

lhe lower end of the aluminum tube 15 is connected to an L-shaped irontube 22 by means of a coupling 23, which is preferably composed ofrubber. The lower end of the aluminum tube 16 is connected to anL-shaped iron tube 24 by means of a rubber coupling 25. The iron tube 24is directly connected to one end of a cylinder 26. The iron tube 22enters the cylinder 26 near one end thereoi and ends near the oppositeend of the cylinder. The cylinder 26 comprises a portion 27 whichextends partly through iron tube the wall of, the furnace and ispreferably composed of iron or Steel. A second portion 28 of thecylinder 26, which is composed of copper, extends into the chamber 2 ofthe furnace and is preferably thread-connected to the portion 27 of thecylinder.

The upper ends of the aluminum tubes 15 and 16 are held together bymeans of a bracket 29. The bracket 29 comprises a frame 30,which-surrounds the two tubes 15 and 16, anda roller 31 which is mountedin the frame 30 between the two tubes. A block 32 is mounted on the tube15 and is held in engagement with the roller 31 by means of a springmember 33 and an adjustable screw 34. A similar block 35, which ismounted on the tube 16, is held in enga ge. ment with the roller 31 bymeans of a sprlng.

member .36 and the screw member 37. Preferably, the surface of each ofthe blocks 32 and 35, which enga the roller 31, are

ved, as shown in F1 2 of the drawing.

The roller 31 is provlded with an elongated ortion or pointer 38, wh1ch'13 d and also bent at right angles to the portion which engages theblocks 32 and 35. An arm 39 is connected near the lower end of theelongated portion or pointer 38 for operating the fluid device 13.

The thermal device above described serves to measure variations in thetemperature of the furnace 1. A uniform stream of water or fluid fromthe source of supply 20 is conveyed, through the aluminum tube 16, the24, the cylinder 26, the furnace, the iron tube 22 and the aluminum tube15, to the drain 21. Accordingly, the aluminum tube 15 is heated inaccordance with the tem erature of the furnace, and, consequently, 51616is relative elongation between the two tubes 15 and 16. Relativemovement between the two tubes is prevented at one end by means of theclam ing member 19.

However, relative elongation between the tubes is permitted and suchelongation 1s measured b the rotative movement of the roller 31. uchrelative elongation between the tubes is indicated by the movement ofthe ointer 38 and is utilized for controlling the uid device 13. Thefluid device, as Wlll be hereinafter set forth, controls the currentimput to the furnace.

plied to the furnace.

A vertical tube 44, having an enlarged head portion 45, is connected tothe cylinder 41, near one end thereof, and serves to supply variablefluid ressure for operating the piston 40. The tu e 44 is provided withan ,outlet 46 adjacent to the cylinder 41, for a purpose to behereinafter set forth. The head portion 45 of the tube 44 supports avalve 47 which serves to admit any amount of suitable fluid to the tube44 for operating the piston 40. The gate member 48 of the valve isdirectly connected to the pointer 38 by means of the arm 39. A source offluid pressure 49 is provided for supplying fluid above the valve 47,and an outlet 50 is provided above such valve in order to maintain aconstant head on it. The outlet 46, which is connected to the tube 44,serves to permit the slow release of the fluid pressure in the tube 44.

Assuming the valve 47 to be in the position shown for supplying fluidpressure through the tube 44 to the cylinder 41, the fluid pressureoperates the brush member 12 toward the left, as shown upon the drawing.Such movement of the brush member 12 increases the number of activeturns of the transformer which is included in circuit with the resistor4, and, consequently, increases the current imput to the furnace. Whenthe temperature of the furnace is increased above a predetermined point,the aluminum tube 15 is so elongated as to effect rotation of the roller31 in a clockwise direction. Such rotation of the roller member operatesthe valve 47 for preventing further fluid pressure being supplied to thecylinder 41. Thereupon, the outlet'46, which is connected to the tube44, slowly removes the fluid pressure from the cylinder 41, and thespring member 43 effects movement of the piston 40 and the brush member41 toward the left, as shown in Fig. 1 of the drawing. Consequently, thenumber of active transformer turns is reduced to lower the current imputto the furnace. When the temperature of the furnace isreduced below apredetermined limit, the thermal device 14 operates the valve 47 foragain supplying fluid pressure to the cylinder 41. The current imput tothe furnace is increased and the above cycle of operations is againrepeated.

Referring to Fig. 4. a modification of my invention is shown, where aconsiderable portion of the fluid device 13 is eliminated. By reason ofthe similarity of the two regulators, like parts will be indicated bycorresponding reference characters.

The cylinder 41 is directly connected to a source of constant fluidpressure 60 and is provided with an outlet 61, which is controlled by avalve 62. The valve 62 comprises a plug 63 which controls the release ofthe fluid pressure from the cylinder 41. In the position shown in Fig.4, the valve 62 is so set as to maintain the fluid pressure in lid lltl

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mounts the cylinder 41. Upon a small movement of the valve plug 63 in acounter-clockwise direction, the outlet 61 is directly connected,through the valve 62, to any suitable drain (not shown). The valve plug63 is directly connected to a link 64-, which is operated by the arm 39.The operation of the regulator shown in Fig, i is similar to theoperation of the regulator shown in Fig. 1, and further descriptionthereof is deemed unnecessar n the regulator system above described, anefiicient and reliable thermal. device is provided for indicating anyminute variation in the temperature of the furnace, and such thermaldevice is utilized for efiiciently controlling the current imput to thefurnace and so maintains the furnace temperature substantially constant.The thermal device is so constructed as to permit the ready replacementor repair of any parts thereof.

Modifications in the system and in the arranement and location of partsmay be u. within the spirit and scope of my invention, and suchmodifications are intended to be covered by the appended claims,

I claim as my inventions i. In a, fumace-regulator system, thecombination with a pair of tubes, and

means for effecting relative elongation be tween said tubes inaccordance with the temperature of the furnace, of means controlled bythe relative elongation between said tubes for regulating thetemperature of the furnace,

2. in a regulator system, the combination with an electric furnace, aconduit for conveying a fluid through said furnace, tubes connected tothe respective ends of said conduit and disposed in parallel relation,and a source of fluid supply connected to one of said tubes, ofa rollerlocated between said tubes and operated in accordance with therelative-elongation between the tubes, and means controlled by saidroller for governing the temperature of the furnace.

3. In a regulator system for an electric furnace, the combination with apair of tubes, and means for effecting relative elongation between shidtubes in accordance with the temperature of the furnace, of meanscontrolled in accordance with the relative elongation between said tubesfor gov erning the current supplied to the furnace.

4. In a regulator s stem for an electric furnace, the combinationcomprising a controller for governing the current supplied to thefurnace, a fluid system passing through said furnace, and means governedby said fluid system for operating the controller to maintain thetemperature of the furnace substantially constant, a

5, In a regulator system for an electric furnace, the combinationcomprising a fluid system passing through the furnace, a corn troller,and mechanical means operated in accordance with the difierence in thetern-- perature of the duid entering and leaving the furnace forgoverning the-operation of said controller to maintain the temperatureof the furnace substantially constant.

6. In a regulator system for an electric furnace, the combination withtwo members and meansfor efiecting relative elongation between saidmembers in accordance with the temperature of the furnace, of meanscomprising a roller located between said members and rotated inaccordance with the relative elongation between vsaid Inenr bors forcontrolling the current imput to the furnace,

7. In a regulator system for an electric furnace, the combination withtwo members, and means for eii ecting' relative elongation of saidmembers in accordance with the temperature of the furnace, of a rollerlocated between said members and rotated in accordance with the relativeelongation between said members, means comprising a controller forgoverning the current supplied to the furnace, and mechanical connectingmeans between said roller and. the controller for operating thecontroller maintain the furnace temperature substantially constant.

8. in a regulator system for an electric furnace, the combination with apair oi members located in parallel relation, and means for effectingrelative movement of said members in accordance with the temperature ofthe furnace, of a controller for governing the amount of currentsupplied to the furnace, and means for mechanically connecting saidcontroller to said tubes to be operated in accordance with the relativeelongation between such tubes.

9. In a regulator system for an electric furnacathe combinationcomprising a fluid system having a one heated in accordance with thefurnace temperature. said fluid system having two tubes located inparallel relation and respectively heated in accord-- ance with thetemperature of the fluid before and after being heated by the furnace,and means operated in accordance with the relative elongation of saidtubes for controlling the current innput to the furnace.

10. In a regulator system for an electric furnace, the combinationcomprising a pair of tubes, means for effecting relative elongation ofsaid tubes in accordance with the variation in furnace temperature, acom troller for governing the current imput to the furnace, and meanscontrolled by the relative elongation of said tubes for operat ing saidcontroller,

11. In a regulator system for an electric.

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furnace, the combination comprising a pair of members having relativeelongation in accordance with the variations n furnace temperature, andmeanscomprising a roller temperature, and means operated by saidoperated by said members for governing the members for governing theimput to the 10 imput to the furnace to maintain its temfurnace tomaintain its temperature subperature substantially constant. stantiallyconstant. p

5 12. In a regulator system for an electric In testimony whereof, I havehereunto furnace, the combination comprising a pair subscribed my namethis 26th day of Octoof members having relative elongation in her 1920.accordance with the variations in furnace GEORGE M. LITTLE

